Electron tube



Mach 9, 1937. s. B. RUBlNsTElN ELECTRON TUBE 4 sheets-sheet 1 Filed July 25, 1928 Jari;

J; a ,INVENT'OR ATTORNEY March 9, 1937.V s, B RUBlNsTEiN l 2,073,598

ELECTRON TUBE Filed July 25, 1928 4 Sheets-Sheet 2 INVENTOR.

BY f3 f f Y `ATTORNEY. f

March 9, 1937.

I S. B. RUBINSTEIN ELECTRON TUBE 4 Sheets-Sheet 3' Filed July 25, 1928 INg/EA/Tolg.

March 9, 1937. s. B. RUBINSTEIN ELECTRON TUBE Filed July 25, 1923 4 Sheets-Sheet 4 Patented Mar. 9, 1937 UNITED s'iarss i genees PATENT OFFICE ELECTRON TUBE Samuel B. Rubinstein, New York, N. Y.

Application July 25, 1928, Serial No. 295,164

8 laims.

My invention relates broadly to electron tubes and more particularly to a construction of electron tube energized by power derived from the usual house lighting mains without the employment of primary or secondary batteries.

One of the .objects of my invention is to provide a construction of electron tube known as the auxiliary heater type where the elements are so positioned within the tube as to reduce'the effect ofnoise inherent in the power supply system upon the sensitive sound reproducing system in which the tubes are connected.

Another object of. my invention is to provide a construction of electron tube having an electron emitter energized by power derived from the usual house lighting mains wherein the filament is substantially velectrostatically and electromagnetically shielded from the grid and plate electrodes within the tube for avoiding the reproduction of alternating current line hum or direct current generator ripple which may be present in the power supply system.

A further object of my invention resides in the construction of an electron tube of the auxiliary heater type wherein the heated filament is formed by a pair of substantially solenoidal shaped windings extending in parallel axes and surrounded r by cylindrical members bearing an electron emitting coating on the exterior thereof maintained in position with respect to a grid and plate electrode for magnetically and electrostaticallyisolating the filament from the gridand plate electrodes.

Still another object of my invention is to provide a Construction of electron emitter for an electron tube of the auxiliary heater type wherein a heated filament is carried by a pair of parallel extending hollow tubular members with concentrically disposed cylindrical members around the lament whereby said cylindrical members may lbe heated by radiation and convection to an electron emitting temperature. y y

`Still further objects of my invention reside in the constructionand arrangement .of parts within an electron tube of the auxiliary heater type and the arrangement of emitter for concentrating the electromagnetic iield established by the passage of heating current through the lament `electrode in a zone substantially isolated from the grid and plate electrodes within the electron tube preventing interference from line variation upon the operation of the electron tube. Other and further objects of my invention reside in the construction and arrangement of parts for an electron tube ofthe auxiliary heater type (Cl. Z50-27.5)

as set forth more fully in the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 shows a circuit arrangement diagrammatically illustrating the application of` the electron tube structure of my invention as a detector; Fig. 2 is an enlarged diagrammatic'view of the electron emitting structure employed in the electron tube of my invention; Fig. 3 is a perspective View of the shield and electron emitting elec- 10 trodes; Fig. 4 is a view of one of the spacer members used for locating the leads of the electrodes within the electron tube structure; Fig. 5 is a cross-sectional view taken through the electron tube structure of my invention; Fig. 6 is a wiring 15 diagram of a complete radio broadcast receiving apparatus employing electron tubes of the structure covered by my invention; Fig. 7 is a view of .one of the electron emitting members employed in the electron emitter structure; Fig. 3 is a cross- 20 sectional view taken on line 8 8 of Fig. '7 through the electron emitter; Fig. 9 is a diagrammatic view illustrating the arrangement of leads to the electrodes within the tube structure; Fig. 10 is a fragmentary View of the insulated support for 25 the leads to the tube electrodes; Fig. 11 is a plan View of the base for the electron tube of my invention; Fig. 12 is a side View of the base illustrated in Fig. l1; Fig. 13 is a theoretical View showing the distribution of the magnetic lines of 30 force comprising the magnetic iield which surrounds the electrodes in the tube structure of my invention; and Fig. 14 is a perspective view showing more clearly the arrangement .of parts of the electron emitter employed in the tube structure 35 of my invention.

Referring to the drawings in detail, I have illustrated the electron tube structure of my invention connected in a radio receiving circuit in Figure l where reference'character l desig- 40 nates the antenna, 2 the ground connection, 3 the primary winding of a coupling transformer, 4 the secondary winding of the coupling transformer, and 5 designates a Variable condenser for tuning the secondary system 4. The electron 45 tube structure of my invention is enclosed within an Vevacuated vessel. 6 and includes a pair of vitreous tubes 'l apertured throughout their entire length. The vitreous tubes l are surrounded by cylindrical members 8 which are arranged 50 within the evacuated envelope E in denite relation to the control electrode 9 and plate electrode l0. In the diagram of Figure 1, the grid electrode 9 is connected at I6 through a lead including grid condenser 23 shunted by grid leak 22 55 with one side of the tuned circuit 4-5. 'I'he plate electrode III is connected through lead 24 and telephones I9 with high potential source represented at which is in turn connected through lead I5 with the cylindrical members 8 and with the opposite side of the tuned circuit 4 5. As more clearly shown in Figs. 2, 7, 13 and 14, the vitreous tubes 'I pro-vide supports for the filament I I which is wound thereon substantially in the nature of a solenoidal winding clamped at the top and bottom by two collars I8 which prevent the filament from unraveling. The ends of the filament, that is the portions extending past the collars I6, are wound around the upwardly extending portions I2@ and I2b of the bridge member I2 which provides a connection between the two solenoidal windings. The opposite ends of the filaments I2 connect to the leads I4a and I4b which pass through the glass stem of the tube represented at 28 in Fig. l1 in the relative positions shown. The cylindrical members 8 which surround the solenoidal filament windings II are connected at opposite ends through conductors I3 and II providing a rigid structure as shown more clearly in Fig. 3 arranged to be supported from extending members 30 and I 5 within the tube assembly. The lighting mains of a residence may be connected directly at the terminals 2 Ia,` and 2 I b for energizing the filament I I. The electrodes within the tube structure are assembled as shown in Fig. 5, wherein insulated members and 26 serve as spacers for the leads extending to the electrodes. The plate electrode is designated at I6 substantially in the form of a cylindrical member supported on conductors 2l anchored at opposite ends in insulated members 25 and 26. One of the conductors continues, as represented at 24 in Fig. 1l to provide a plate lead to the electron tube. The grid electro-de 9 surrounds the electron emitter and is disposed adjacent the interior of the plate electrode and is formed by a spirally wound conductor on wire supports 29 which extend between insulated members 25 and 26, one of the conductors extending as represented at I6 to provide a connection to the grid electrode. The electron emitter is centered within the tube structure by means of member 36 extending into insulated member 26, and by the extension of member I2a; into the insulated member 26, the lead to the electron emitter 8 extends through the stem of the tube as represented at I5. The leads with the ends of the filament II extend to the stem of the tube as represented at I4a and I4b. The members I4a and I4b may be suitably secured to the ends of the bands I8 as illustrated more clearly in Fig. 8.

The tube structure may be mounted in an insulated support 49 represented in Figs. 11 and l2 with power terminals 5I 52, 53 and 54 protruding therefrom. The bayonet slot pin member 5l] is positioned in one side of the adaptor to permit the tube to be inserted readily into the standard socket face. A shelf-like member 51 extends from the top of the base 49 and carries binding posts 55 and 56 thereon through which connections may be established with the lighting circuit and thence to the filament terminals in the electron tube.

In Fig. 6, I have illustrated the application of the tube of my invention to a radio broadcast receiving set constituted by two stages of radio frequency amplification at 3I-32 with coupling transformer 36 therebetween, a detector tube 33 coupled to the output of the radio frequency amplification system through transformer 3l and audio frequency amplification stages constituted by electron tubes 34 and 35 connected through coupling transformers 38 and 39. The primary winding of transformer 38 may be shunted by bypass condenser 40. The lament heating circuit is completed through leads 4'I and 48. Terminals 4I, 42, 43, 44, 45 and 46 are provided to impress the required operating potential on the remaining circuits of the several electron tubes in the receiving system.

The electron tube structure of my invention is provided with that kind of an auxiliary heater which will permit the interior walls of the electron emitting members 8 to be heated by radiation and convection heat currents from filament II. The vitreous tubes 'I have a hollow interior throughout their length to permit the uniform distribution of convection currents for heating the cylindrical members 8.

The heat radiated and that received from the convection currents is absorbed by the members 8 composed of concentric cylindrical nickel tubes which are coated on the outside surfaces only, by a radio-active or electron emitting salt of the barium, strontium and calcium group. The heat received by the members 8 is sufficient to make the radio-active material emit electrons which bombard the anode I0 under control of grid 9.

Either alternating or direct current may be supplied from the house lighting mains for energizing the filament windings I I and it is unnecessary to interpose a transformer in the circuit.

It will be observed in Fig. 13 that the magnetic field set up by the passing of current through the solenoidal filament windings II represented by dotted lines 60 are concentrated within electron emitter, turning upon itself through the hollow cores of the windings I I. The independent magnetic field of each solenoidal winding I I may take the path represented at 60a and 60h but this path is substantially confined within the cylindrical members 8 thus preventing leakage of the magnetic eld through the grid and plate electrodes and the setting up of undesirable noises in the circuits connected to the electrodes.

In order to further prevent the setting up of noises in the circuits of the electron tube system, I extend the cylindrical members 8 with respect to the lament windings II for a longer length with respect to the length of the grid 9 to substantially shield the grid.

The electron emitter is maintained at ground potential so that induced voltages on the cylindrical members 8 may be by-passed with respect to the other electrodes of the tube. The lead I6 extending from the grid is shielded from the high voltage lines as illustrated in Fig. 11 by spacing this lead therefrom with the grounded lead I5 interposed therebetween. This same practice is followed at the upper end of the support for the tube electrodes where the grid support I 6 is spaced from the high voltage source existent at I2a by the grounded lead 30 or spaced at a substantial distance as represented by the spacial relation between the lead 29 and the lead I2a along the insulated member 26.

The tube construction of my invention has been found to be extremely practical in its construction, manufacture and operation, and while I have described a preferred embodiment of my invention, I desire that it be understood that modications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

CII

1. An electron tube of the auxiliary heater type comprising a pair of parallel extending tubular members each providing an insulated core for the support of a filament winding thereon, bands encircling the extremities of said tubular members and establishing electrical connection with the ends of the filament, a bridge member interconnecting the bands at the upper extremities of said tubular members, and a pair of cylindrical members encircling said tubular members and carrying electron emitting coatings thereon.

2. An electron tube of the auxiliary heater type comprising a pair of hollow cylindrical members comprising a pair of vitreous tubular members,

means for mounting said members in parallel relationship spaced one from the other comprising individual means embracing and supporting each of said members at the lower extremities thereof and conductive means embracingv the upper extremities of said members and interconnected for maintaining the spacial relation of said members at the upper extremities thereof, a filament Wound along said members, a pair of cylindrical elements enclosing each of said tubular members, and grid and plate electrodes concentrically positioned around said cylindrical elements, said cylindrical elements being substantially longer than said grid and plate electrodes, whereby said grid and plate electrodes are substantially shielded from the effects of said filament.

4. In an electron tube of the auxiliary heaterl type, an electron emitter including a heater member consisting of a pair of iilamentary windings disposed on spaced parallel axes with respect to each other for concentrating the eiects of the magnetic fields thereof within a central zone in said electron tube, grid and plate electrodes concentrically disposed around said heater member, electron emitting surfaces enclosing and spacially related to each of the iilamentary windings constituting said heater member and operating to emit electrons under control of said heater member and shielding said grid and plate electrodes from the magnetic effects of said lamentary windings and means at each end of said electron emitting surfaces for maintaining said pair of filamentary windings in predetermined relation to said electron emitting surfaces.

5. In an electron tube of the auxiliary heater type, an electron emitter comprising a pair of filamentary windings disposed in parallel relation one with respect to the other, cylindrical members enclosing said ilamentary windings and spaced therefrom in concentric relation thereto, each of said cylindrical members having electron emitting coatings thereon, means connected at opposite extremities of each of said cylindrical members for maintaining said cylindrical members at equi-potential and means extending laterally of said pair of illamentary windings for maintaining said windings centrally of said cylindrical members.

6. An electron emitter for vacuum tubes of the auxiliary heater type comprising a pair of parallel extending tubular members, heating laments wound on said tubular members, means embracing opposite ends of said tubular members, a bridge member extending between said means at one end of said tubular members for supporting said tubular members at their upper extremities in xed spacial relation and providing an electrical connection between said heating filaments, terminal connections between the ends of the heating filaments and the means embracing adjacent ends of said tubular members, and a pair of cylindrical members surrounding said tubular members in spaced relation to the heating filaments, said tubular members having electron emitting surfaces thereon.

7. A cathode structure for electron tubes comprising a rod member of insulating material, a cathode member surrounding said rod member, a heater lament spirally wound on said rod member, clamping devices engaging opposite ends of said rod member, a connection between the ends of said heater filament and said clamping devices, and terminals and supporting means extending from said clamping devices for centering said rod member in spacial relation to said cathode member.

8. A cathode structure for electron tubes comprising a tubular cathode member, a rod of insulating material extending axially through said tubular cathode member, metallic bands embracing opposite ends of said rod member, means extending from said metallic bands for centering said rod member with respect to said tubular cathode member and supporting said rod member with respect thereto, and a spiral heater lament mounted on said rod member and having its opposite ends electrically connected to the respective metallic bands at opposite ends of said rod member.

SAMUEL B. RUBINSTEIN. 

